1. Field of the Invention
The invention relate to a display device.
2. Discussion of the Related Art
A two-dimensional display device is generally used. Recently, because of wideband communication networks, a three-dimensional display device has been researched and developed.
There are various types of three-dimensional image displays with various types, for example, a volumetric type, a holographic image type, a stereographic type and the like. The volumetric type is used for three-dimensional computer graphics or an I-MAX movie. The holographic type is used for a holographic image. The volumetric type and the holographic type require large amounts of data and result in a high cost. So, presently, the stereographic type is used widely.
The stereographic type display device displays a three-dimensional image using binocular parallax. When the right and left eyes look at respective two two-dimensional images, the two two-dimensional images are transferred to the brain and then the brain mixes the two two-dimensional images. Thus, three-dimensional images having depth and reality are perceived. The stereographic type display device includes a display device that uses specific glasses and a display device without glasses. The stereographic type display device without glasses is preferred to the stereographic type display device that uses the specific glasses because the stereographic type display device without glasses does not need the separate glasses. The stereoscopic display devices without glasses are divided into a parallax barrier type, a lenticular type, and the like. Of these types, presently, the parallax barrier type has been typically used.
FIGS. 1A and 1B are perspective and cross-sectional views, respectively, illustrating a parallax barrier type display device according to the related art.
Referring to FIGS. 1A and 1B, the parallax barrier type display device 11 includes a liquid crystal display panel 15 having a plurality of pixels P, a backlight unit supplying light to the liquid crystal panel 15 and including a reflection sheet 35, a plurality of lamps 20 and a plurality of optical sheets 25, and a parallax barrier 30.
The liquid crystal panel 15 includes right and left eye pixels alternately arranged to simultaneously display a left-eye image and a right-eye image. The parallax barrier 30 includes barriers 31 and slits 32 alternately arranged for light from the left-eye and right-eye pixels to selectively pass through the parallax barrier 30. A viewer combines the left and right images to perceive a three-dimensional image by parallax of both eyes.
However, because the related art parallax barrier type display device uses the parallax barrier blocking light through the barriers, brightness is reduced.
Further, because the related art parallax barrier type display device is used only as a three-dimensional display device, it can not normally display two-dimensional images.